Field of the Invention
The invention relates to a method and a circuit configuration for the transmission of message units associated with message streams of different priority, jointly through one transmission channel. Such a method and such a circuit configuration are already known from German Published, Non-Prosecuted Patent Application DE 197 05 789 A1.
That method and that circuit configuration are intended to solve the problem of allowing the transmission lines in an ATM system and the buffer storage devices respectively associated therewith to be utilized efficiently. To that end, the invention provides that, in the case of a buffer storage device which is filled to a specific level, when a message cell which is associated with a virtual connection of relatively high priority arrives on the respective transmission line, one or more of the message cells (which are currently stored in the buffer storage device) of a selected virtual connection of low priority is or are discarded as a function of the number of lower priority stored message cells for that virtual connection.
U.S. Pat. No. 5,268,900 discloses a method for the transmission of message units which are associated with message streams of different priority and traffic class, jointly through one transmission channel. In that method:
the message units associated with the respective message stream each pass through a queue which is specific to the priority and traffic class; PA1 the queues are combined on the basis of their traffic classes to form queue groups; and PA1 the queue groups are each controlled by a separate queue control device in such a manner that queues are combined to form partner queue groups which are specific to the traffic class, where they have priorities that differ for the same traffic class.
An article entitled "Methodologies for bandwidth allocation, transmission scheduling, and congestion avoidance in broadband ATM networks", by K. Sriram, in Computer Networks and ISDN Systems 26, 1993, pages 43-59 discloses an operating strategy for message streams of different priority through a joint transmission channel. In that device, a plurality of queues are controlled on the basis of their priority in such a manner that one queue is exclusively prioritized with respect to the remaining queues, in that transmission of message units from one of the remaining message units is allowed only in the case where no message units can be transmitted from that queue with maximum priority.